Recovery from sexual exhaustion-induced copulatory inhibition and drug hypersensitivity follow a same time course: two expressions of a same process?

Male rats allowed copulating without restriction with a single oestrous female ejaculate repeatedly until reaching sexual exhaustion. Twenty-four hours after this process, sexually exhausted males exhibit a series of physiological alterations when compared to non-exhausted males. Among them, the most conspicuous are a long-lasting sexual behaviour inhibition and a generalised hypersensitivity to drug actions. The objective of the present work was to establish if there was a correlation between these two features of sexual satiation in relation to the duration of its expression. To that aim, we characterised the spontaneous sexual behaviour recovery process from sexual satiation, as well as the duration of the drug hypersensitivity phenomenon. The latter was assessed through the appearance of a sign of the serotonergic syndrome: the flat body posture. Results showed that the drug hypersensitivity phenomenon and the sexual inhibition that results from copulation to satiation follow a similar time course of recovery, with a drastic decrease in their expression 96 h after the sexual satiation process. This finding indicates that these phenomena might represent two expressions of a same brain plasticity process, as suggested by the long lasting character of both events, which interestingly appears to be reversible.